In the oil and gas industry, production logging is utilized to determine the gas and water phases of a multi-phase production flow, such as to develop production and/or remedial strategies. However, in lateral wells or well portions that are substantially horizontal, the heaviest phase (e.g., water in a water-oil-gas flow) segregates towards the bottom of the production tubing, and the lightest phase (e.g., gas in a water-oil-gas flow) segregates towards the top of the production tubing. Such gravity-induced segregation creates challenges when operating production-logging tools to determine composition of the gas phase, because the sensors of such production-logging tools may not be located within the cross-sectional portion of the production tubing that substantially contains the gas phase. For example, when the measurement region surrounding the sensors is substantially occupied by liquid, the resulting data is useless and discarded.
Such sensors also include an optical window serving to isolate the production flow from the actual sensing element of the sensor. However, oil from the production flow may foul the optical window. Such fouling can also adversely affect sensor data, and perhaps render the sensor functionally blind.